Pulmonary vasoreactivity to endothelin-1 at elevated vascular tone is modulated by potassium channels

Research output: Contribution to journalArticle

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Abstract

The role of K+ channels on the presser effect of endothelin-1 (ET-1) on vascular resistance and compliance in the canine pulmonary circulation was studied by using three different K+ channel inhibitors in isolated blood- perfused dog lungs when vascular tone was elevated with U-46619: 1) 10-6 M glibenclamide, a potent and selective blocker of ATP-sensitive K+ channels; 2) 1 mM tetraethylammonium ions (TEA), an inhibitor of Ca2+-dependent K+ channels; and 3) 10-4 M 4-aminopyridine, a nonspecific inhibitor of K+ channels. The results of the present study showed that under control vascular tone, 10-8 M ET-1 increased total vascular resistance and capillary pressure by increasing postcapillary resistance. In addition, ET-1 decreased total vascular compliance. When vascular tone was elevated, ET-1 elicited an initial transient vasodilation followed by a sustained mild vasoconstriction that was lesser in magnitude than that observed under normal vascular tone. In addition, the increases in postcapillary resistance and capillary pressure and the decrease in vascular compliance that was observed with ET-1 at normal vascular tone was not present. Pretreatment with glibenclamide, TEA, and 4- aminopyridine at elevated vascular tone significantly potentiated the presser effect of ET-1, and TEA blocked the transient vasodilation to ET-1. These data indicate that when pulmonary vasomotor tone is elevated with U-46619, Ca2+dependent K+ channels may play a significant role in mediating the vasodilator response to ET-1 while ATP-sensitive, Ca2+-dependent, and other voltage-activated K+ channels attenuate the pulmonary vasoconstrictor response to ET-1.

Original languageEnglish (US)
Pages (from-to)91-98
Number of pages8
JournalJournal of Applied Physiology
Volume80
Issue number1
DOIs
StatePublished - Jan 1 1996

Fingerprint

Potassium Channels
Endothelin-1
Blood Vessels
Lung
Tetraethylammonium
Compliance
15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid
4-Aminopyridine
Glyburide
Vasodilation
Vascular Resistance
Capillary Resistance
Adenosine Triphosphate
Pressure
Pulmonary Circulation
Vasoconstrictor Agents
Vasoconstriction
Vasodilator Agents
Canidae
Dogs

Keywords

  • glibenclamide
  • pulmonary capillary pressure
  • pulmonary vascular compliance
  • pulmonary vascular resistance
  • tetraethylammonium ions
  • vasoconstriction

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Cite this

Pulmonary vasoreactivity to endothelin-1 at elevated vascular tone is modulated by potassium channels. / Barman, Scott A.

In: Journal of Applied Physiology, Vol. 80, No. 1, 01.01.1996, p. 91-98.

Research output: Contribution to journalArticle

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abstract = "The role of K+ channels on the presser effect of endothelin-1 (ET-1) on vascular resistance and compliance in the canine pulmonary circulation was studied by using three different K+ channel inhibitors in isolated blood- perfused dog lungs when vascular tone was elevated with U-46619: 1) 10-6 M glibenclamide, a potent and selective blocker of ATP-sensitive K+ channels; 2) 1 mM tetraethylammonium ions (TEA), an inhibitor of Ca2+-dependent K+ channels; and 3) 10-4 M 4-aminopyridine, a nonspecific inhibitor of K+ channels. The results of the present study showed that under control vascular tone, 10-8 M ET-1 increased total vascular resistance and capillary pressure by increasing postcapillary resistance. In addition, ET-1 decreased total vascular compliance. When vascular tone was elevated, ET-1 elicited an initial transient vasodilation followed by a sustained mild vasoconstriction that was lesser in magnitude than that observed under normal vascular tone. In addition, the increases in postcapillary resistance and capillary pressure and the decrease in vascular compliance that was observed with ET-1 at normal vascular tone was not present. Pretreatment with glibenclamide, TEA, and 4- aminopyridine at elevated vascular tone significantly potentiated the presser effect of ET-1, and TEA blocked the transient vasodilation to ET-1. These data indicate that when pulmonary vasomotor tone is elevated with U-46619, Ca2+dependent K+ channels may play a significant role in mediating the vasodilator response to ET-1 while ATP-sensitive, Ca2+-dependent, and other voltage-activated K+ channels attenuate the pulmonary vasoconstrictor response to ET-1.",
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